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From: Christoph Hellwig <hch@infradead.org>
To: Andreas Dilger <adilger@dilger.ca>
Cc: Andy Lutomirski <luto@mit.edu>, Nick Piggin <npiggin@suse.de>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Al Viro <viro@ZenIV.linux.org.uk>,
	Ulrich Drepper <drepper@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [rfc] new stat*fs-like syscall?
Date: Fri, 25 Jun 2010 02:37:55 -0400	[thread overview]
Message-ID: <20100625063755.GB4128@infradead.org> (raw)
In-Reply-To: <9AFEC906-4EC6-49F3-8644-9230934E1D2C@dilger.ca>

On Thu, Jun 24, 2010 at 05:06:45PM -0600, Andreas Dilger wrote:
> I think the right solution for this issue is to (gradually) start enforcing the "uniqueness" of the UUID in the filesystem superblock.  That is what it is supposed to be for.  Using (fsid, st_inode) doesn't necessarily help anything, if "fsid" isn't unique, and the same "st_inode" number is used on two different mountpoints.
> 
> To start, tracking the UUID at mount time an printing a non-fatal error at mount time if the mounted UUID is not unique would help, as would having e.g. fsck track the UUIDs of the underlying filesystems and printing a non-fatal error if it hits a duplicate UUID.  
> 
> At some point in the future, the kernel can be changed to refuse to mount a filesystem with a duplicate UUID.  I believe mount.xfs already does this.

Tracking and exposing the uuid to be exact.  Having the full uuid in a
statfs/statvfs-like system call is one first step.  And yes, XFS does
check the uuid during mount.  But it's actually in kernelspace, not in a
mount helper which XFS doesn't have.  Take a look at xfs_uuid_mount().

  reply	other threads:[~2010-06-25  6:37 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-24 13:14 [rfc] new stat*fs-like syscall? Nick Piggin
2010-06-24 14:03 ` Miklos Szeredi
2010-06-24 14:36   ` Nick Piggin
2010-06-24 14:08 ` Andy Lutomirski
2010-06-24 14:18   ` Miklos Szeredi
2010-06-24 14:37     ` Andrew Lutomirski
2010-06-24 14:48       ` Miklos Szeredi
2010-06-25  3:50         ` Nick Piggin
2010-06-24 23:06   ` Andreas Dilger
2010-06-25  6:37     ` Christoph Hellwig [this message]
2010-06-24 23:13 ` Andreas Dilger
2010-06-25  4:01   ` Nick Piggin
2010-06-25  4:33     ` Jeff Garzik
2010-06-25 17:47     ` Andreas Dilger
2010-06-25 17:52       ` Ulrich Drepper
2010-06-25 18:16         ` Christoph Hellwig
2010-06-25 18:45           ` Christoph Hellwig
2010-06-25 19:40             ` Ulrich Drepper
2010-06-26  5:53 ` J. R. Okajima
2010-06-26  9:35   ` Christoph Hellwig
2010-06-26 12:54     ` J. R. Okajima
2010-07-05 20:58       ` Brad Boyer
2010-07-05 23:31         ` J. R. Okajima
2010-07-06  0:45           ` Brad Boyer
2010-07-06 16:45             ` Linus Torvalds
2010-07-07  1:44               ` Christoph Hellwig
2010-07-07  2:28                 ` Linus Torvalds
2010-06-26 14:49     ` Ulrich Drepper
2010-06-26 10:13 ` Andi Kleen

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